Rubber wood sawdust (RBS) represents a prominent agricultural waste, notable for its high lignocellulose content. This unique composition not only renders it eco-friendly but also offers enhanced mechanical strength, biodegradability, and cost-effectiveness, making it a promising candidate for composite materials. Beyond its traditional role in the mushroom industry, the potential of RBS is increasingly recognized in the realm of sustainable composites, especially in mycelium composite technology. This study delves into creating a biodegradable composite that effectively harnesses this waste. This study assessed critical inoculation conditions, such as moisture content (50 to 80%), pressing temperatures, and oxygen availability, for their influence on the properties of mycelium-based composites (MBC). Thermogravimetric analysis pinpointed mycelium degradation at 270 degrees C, tied to chitin disintegration, with RBS fiber initiating weight loss at 250 degrees C. Notably, MBC panels pressed at 130 degrees C surpassed mycelium-free controls (CRM) in flexural strength, stability, and morphology. SEM investigations further emphasized the mycelium as self-binding matrix microorganism in the composite, enhancing void filling and bonding. These findings highlight the suitability of RBS as a waste-derived material in mycelium composites, paving the way for innovative, eco-conscious applications.